Daikin Outdoor Unit For Reverse Cycle System RY100LUY1

Warning: Do not touch the energized part (high voltage part) for at least 10 minutes after the power is turned OFF.

Be sure to touch the earth terminal with a hand to release static electricity from the body (to prevent PCB from being damaged).

Residual electric charge of the power transistor (should be DC 50V or less)

Remove the wire connecting the power transistor and the compressor. Remove it from the compressor terminal side. During this work, be careful not to deform. Faston terminal at the end of the relay wire.

Resistance measurement for phase 1

Resistance measurement for phase 2

Resistance measurement for phase 3

Is the resistance value equal to 5 times or more than the other resistance values?

Check for Fan Motor Connector (Signal Line)

(2) With the fan motor connector disconnected, measure the resistance between each pin, then make sure that the resistance is more than the value mentioned in the following table.

(2) With the fan motor connector disconnected, measure the resistance between each pin, then make sure that the resistance is balanced in ±30%.

Check for Fan Motor Connector (Power Supply Line)

With the relay connector disconnected, measure the resistance between UVW phases of the connector (3 cores) at the motor side, then make sure that the resistance between each phase is balanced and not short-circuited.;

(1) Set operation OFF and power OFF. Disconnect the connector.

(2) Check that the voltage between the pins 3 - 4 is about 15 VDC.

(3) Check that the voltage between the pins 1 - 4 is about 5 VDC.

(4) Keep operation OFF and power OFF. Connect the connector.

(5) Check whether 2 pulses (0 and 5 VDC) are output 4 times at the pins 1 - 4 when the fan motor is rotated 1 turn by hand.

If NG in steps 2 and 3 Defective PCB

Diagnosis of inadequate refrigerant in cooling operation

Suction superheated degree increases due to refrigerant shortage

Decreased evaporator capacity caused by refrigerant shortage

Compressor frequency decreases despite a large difference between temperature set by the remote controller and suction air temperature

Electronic expansion valve remains fully open and suction superheated degree further increases

Diagnosis of inadequate refrigerant in heating operation

Suction superheated degree increases due to refrigerant shortage

Compressor frequency decreases because suction superheated degree is controlled to prevent oil to the outdoor unit heat exchanger from being retained

Evaporator capacity and compressor frequency decrease despite a large difference between temperature set by the remote controller and suction air temperature

Procedure for checking outdoor-outdoor unit transmission wiring for broken wires

Turn OFF the power supply to all equipment

Short circuit between the outdoor-outdoor unit terminal F1 and F2 in the 'Outdoor Unit A'

Conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the centralized remote controller using a multiple meter

Is there continuity between the said terminal blocks?

If there is no continuity, the transmission wiring may have broken wires

With the outdoor-outdoor unit terminal of the 'Outdoor Unit A' short circuited, conduct continuity checks between the transmission wiring terminal blocks F1 and F2 of the unified ON/OFF controller

Procedure for checking indoor-outdoor unit transmission wiring for broken wires

Turn OFF the power supply to all equipment